Opposed contact measuring device having adjustable transmission



Allg 12, 1952 F MALAGRINO 2,606,369

OPPOSED CNTACT MEASURING DEVICE HAVING ADJUSTABLE TRANSMISSION Filed Jan. 14, 1947 l l In V n for 32 V n Fran effe/)4Q /a rma ,4 AHV/Way Patented Aug. 12, 1952 y 2,606,369 .Y ,Y Y 'i j) rPosEncoNTAcr MEAlsURNG niivica-f g `lanav-rivafieras-T-ABLE 'rRANsiinssroNvy l Francesco llrialagrine, Valenza-,YItaly..Y Y

:Application January I'14, 1947; serial Nettetal' '-In ItalyA J anuary 19,1946

' sciame (c1. asf- 147) 1 This invention relates toga centesimalfemicrcmeterof the snap? typefor the measurefoi bores, which Yisl considerably.J superior.V in keiilciency to the known instruments of this. kind. Y v y An object lof i' this invention 4is toxfprovide .1an apparatus ofA the type reierredtof 'above comprising `mbox-shaped .memberA having 'a measuring arm, a pointer foriindicatinglthe' millimeters, and a dial forindicatingfractionsof millimeters, a member movable in said box-shapedmember having a measuring arm anda millimeterscale cooperating with saidmeasuring'armA 'and said pointer, respectively, al spring interposedvbetween saidY members for urging 'the 'measuringrar'ms apart from each Votl'ierf a` handf'actuated pushbotton'fordrawing together said measuring arms against the action of; said spring, and;adjustable meansv for transmitting the Vmovement'rof .said movable memberito the pointer'lon said dial.

l A further objectrof this invention is'to ,provide in an apparatusy offthe type .referredtoy above, Worm screwtr'ansmission meansfaotin'g. as a; rack for transmitting the rectilinear movement ci the movable member-.to thepointerV on the dial-for indication of fractions of a millimeter, and asV a helicalA gear for transmitting'to the pointenfon said dial correctional angular displacements-imparted-tothe Worm screw., forl correcting any errori in readingdu'e to slight .play or inaccuracy iii-construction' oli-the.indieatingjdevice.

A-further object of vthis'inventiongis to provide in an apparatus ofthe type referred to abovea pin frictionally coupled with the Worm screw and engaged by-a shapedv slot cut in theibox-shaped member and .determining over.V a predetermined range the angular movementtconferred by-hand to the worm screw.` g

A furtherobject ofthis inv'ention'is to' provide in an apparatusl oi :thetype: referred to above, antifriction 'bearings f. for' the f movable member, of which two at least `are adjustablen forallowing for any play between the boxls'haped memberfand the movablermember.

. Further Y features of the micrometer; according to this invention shall v-be moreV fully 'ex-plained With'reference totheienclosed drawings on which: v Figure 1 is a front elevation Vof the instrument looking toward. the Vface of the dial, the arms-.ibeing drawn together and fitted with the expansion Shanks. n n

Figure 2 is a rear elevation fromthe opposite side,V the arms being `drawn together .and the expansion Shanks beingv removed. U

Figure 3 is a rear elevation, thevcover being removed. v

. -2 .Figure 4 is a sectional viewfonfanenlarged scale taken onlineIV-IV ofvFig.-1 1 Y .l

. Figure 5 is a'sectional view on an enlarged scale taken on line VQV. of Fig. 3. Y y

Figure 6 is a detail View of the pin ntted on the worm screw actuating therpointer on the dial indicatingthe lfractions of aN millimeter.

Figure' -is a detailffront view showing an expansion `shank to fbe `iitted on the anvil carrying arms. Figure 8 is a 'plan View ofthe shank. y vReferring toFigures 1` to 6; I denotestlie stationary. member of the micrometer carrying the arm I provided with an-anvil 2. 3 denotes. the movable member of the instrument carrying the armv3 -havinggthevanvil'll :Iittedqthereta The member I is hollow and forma; together with the cover I4, a `box-sl'1aped closed casing enclosing the movable member. y

IThe movable `member slides on suitable guides on the'stationary member I and on ithe ooverl ifi witiithe interposition oi roliers or'balls 32, 33 and .34..carried by suitablegcages, each or" which may ca'rry as fevvy as `two rollers on balls only, maintainingthem perfectly adjusted andnwith the .desiredrspacing these .two-rollers or balls being l'suilicientt ifor the translation j movement performed' by. the movable imember 3: e. `The "position-fof the rollers-.33 Vand 34 is adjustable by means sliding platesl'iSqLi in vorder to make up for any-play ofthe member; i

The member rlisactedupon'bys'a coiled spring 5, Whichtends to hold theearm 3 away'frorr the arm V"I and; consequently, the anvil 4 apart from the anvil llover-the maximum@ displacement or" the member 3. iThe'latterlias 'secured'thereto on one side the-pin -2'I4 mounted forrdisplacement within .the rectilinear slot 25 out inthe Vmember I and llimiting` 'the vmovement cil the movable member. .The member3 Vis-caused to slide `by pressing tlieno'uter knob "35 one finger-of the handfl'Tlii's. compresses the spring 5 and y Sand-anvil toward the arm I 'of the element I. On `releasingthe knob ',Y the spring acts onthe member 3 moving th`e`a'rm 3 vavvay from the arm I"k until the anvil abuts the Work or untilthe pin26 abuts the end'of the s101725. Q v l Aseale -I 5 subdivided into millimeters is secured tothe outside off-the movablemeinber 3Qr directly engraved thereon and corresponds in length to the .maximum strokeoi the ,member 3. The'scale coacts with a pointer I1, adjustablyfattachedto the` stationary" member I by l Whiclr` the fdistance between the outer surfaces of the anvils 2 and 4 can be read.

A spindle 36 is rotatably mounted in the movable member 3 and has a portion 31 provided with a worm-screw meshing with the teeth of a pinion 38 with helical teeth. The pinion may be rotated either by an axial displacement or by an angular displacement of the worm screw 31, that is, this screw acts both as rack and as transmission worm screw with respect to the pinion 38.

The pinion 38 has fixed thereto a toothed wheel 39 meshing with a pinion 40 keyed to a pin, having the pointer I2 for the dial I3 fixed to one of its ends. The dial is provided with a graduation over a full circumference including a hundred equal divisions each of which corresponds to 1/100 millimeter displacement of the member 3'r and anvil 4, the distance between two subsequent divisions being such that it is possible to estimate by approximation W100() millimeter. The transmission ratio between the worm screw 31 and the pinion 4I) is such that a displacement by exactly one millimeter of the member 3' causes the pointer I2 to perform exactly a full turn over the dial I3.

For the purpose of greatest accuracy of readings of fractions of a millimeter on the dial and of allowing for possible slight errors in indication caused by imperfections and play in the teeth of the gears transmitting motion to the pointer,

the worm screw 31 is provided with a correcting device. This device consists of a pin 4I connected to the screw 31 by means of a friction coupling. The pin serves for directing the movements of the worm screw due to displacements of the member 3 in a given direction. The pin 4I, which is frictionally connected to the screw 31 by means of a collar 42 (Fig. 6) clamped on the screw 31 by means of a small bolt 43, slides within a shaped slot 44 (Fig. 2) under the action of Vthe sliding movements imparted to the screw 31. The slot 44 is formed by two plates 45 and 45' secured to the member Iv; the plate 45' being secured to the member I bymeans of a screw and slot connection, in such manner that they may be drawn towards each other. By moving lin the'slotl 44 in either direction the pin 4I imparts slightanguiar movements in either direction to the screw 31, by which they are transmitted to the pinion 40, thereby correcting in either sense the readings on the dial I3 by means ofthe pointer I2, the slot 44 being shaped in such manner as to correct the indication for slightest play or inaccuracies in construction of the transmission gear. As mentioned above, the collar 42V is frictionally coupled to the screw 31 in order to set the pointer I2 at zero in the case the pointer should not resume this position after reading has been effected.

The end ofthe rod 36 is provided with nutshaped extension 46 operable by means of a suitable spanner. By rotating the spindle 36 through small angles by means of the Spanner without carrying along the collar 42 which is prevented therefrom by the pin 4I retained by the the pointer I2 is returned to its initial position without any change in the relative rposition `of the other members.

The expansion Shanks adapted to enlarge the measuring range of the micrometer, which are fitted on the anvil-carrying arms of the instrument, are shown in Figures '1 and 8. Each shank consists of a plate 41 provided near its lower end with a projecting pin 48, which extends through a bore 49 in the arms I' and 3. The, plate is formed above the pin 48, with a slot` in the Slot 44',

4 form of an arc of a circle having its centre on the axis of the pivot 48. When the pivot 48 extends through the bore 49 and the plate 41 is rotated toward the arm, the slot 50 engages a pivot screw 5I, threaded into a tapped hole in the arm I' or 3', thereby clamping the plate 41 to the arm.

The plate 41 has secured to its upper end a pin 52 which, when the expansion shank is fitted on the arm I' or 3' is in line with the anvil 2 or 4. A roller 53 is fitted at the inner end of the pin 52 and turns on a pivot 54; and anvil 55 of hard material being secured to the other end of the pin 52. The distance between the outer surface of the roller 53 and the outer face of the anvil 55 is adjusted at a fixed predetermined value.

It is possible to t Shanks having pins 52 of diierent lengths and either of the arms I or 3 or both of them may be fitted with a shank, whereby the instrument is adapted to operate over a very wide range.

Displacement of the movable member with respect to the stationary member takes place under the action of the spring 5 which tends to push back the rack 31. Therefore, the movable member 3 carrying the arm 3 is displaced with respect to the stationary member I so as to automatically cause the indicating arms to diverge as they are introduced into the recess to be measured.

What I claim is:

1. A gauge for measuring holes, comprising a box-shaped member having a measuring arm, a pointer for indicating millimeters, a dial for indicating fractions of a millimeter and a `second pointer cooperating with said dial, a member movable in said box-shaped member and having a measuring arm and a millimeter scale cooperating with said rst mentioned measuring arm and pointer, an adjustable transmission for transmitting the movement of said movable member to the second pointer, a spring between the box shaped member and the movable member for drawing apart said measuring arms, and a manually actuated push-button for drawing together said measuring arms against the action of said spring;

2. A gauge for measuring holes, comprising ,a box-shaped member having a measuring arm, a pointer for indicating millimeters, a dial for indicating fractions of a millimeter and a second pointer cooperating with said dial, av member movable in said box-shaped member andhaving a measuring arm and a millimeter scale cooperating with said rst mentioned measuring arm and pointer, a worm screw gearing, having a worm screw rotatably mounted in said movable member, and a gear rotatably mounted in said boxshaped member and operatively connected with the second pointer, said worm screw acting as a rack for vtransmitting the translationalmovement of the movable member to the pointeron said dial, and being rotatable by hand to correct any play in the transmission, a spring between the box-shaped member and the movable member for drawing apart said measuring arms, and a hand-actuated push-button for drawing together said measuring arms against thefaction of said spring. f I

3. A gauge for measuring holes, comprising a box-shaped member having a measuring arm, a pointer for indicating millimeters, a dial for indicating fractions' of a millimeter and a second pointer cooperating with said dial, a member movable in said box-shaped member and having a measuring arm and a millimeter scale cooperating with said rst mentioned measuring arm and pointer, a wormscrew mounted for rotation in said movable member, a gear mounted in said box-shaped member and meshing with said wormscrew and operatively connected with the second pointer, the translational movement of said movable member being transmitted to said gear by said wormscrew acting as a rack, a pin frictionally coupled with said wormscrew and engaged by a shaped slot formed in said box-shaped member for correction of any play inthe worm gear transmission, a spring between the boxshaped member and the movable member for drawing apart said measuring arms, and a handactuated push-button for drawing together said measuring arms against the action of said spring.

4. A gauge as claimed in claim 3, in which the shaped slot is formed by plates adjustably mounted on the box-shaped member.

5. A gauge for measuring holes, comprising a box-shaped member having a measuring arm, a pointer for indicating millimeters, a dial for in dicating fractions of a millimeter and a second pointer cooperating with said dial, a member movable in said box-shaped member and having a measuring arm and a millimeter scale cooperating with said rst mentioned measuring arm and pointer, antifriction bearings for said movable member mounted in said box-shaped member, at least two of which being adjustable to allow for any play between said members, a transmission for transmitting the movement of said movable member to the pointer for said dial, pin and slot means coacting with the transmission and making correction of any play therein, a spring between the box-shaped member and the movable member for drawing apart said measuring arms,

and a hand-actuated push-button for drawing together said measuring arms against the action of said spring.

6. A gauge as claimed in claim 3, in which the wormscrew is provided with a nut-shaped eX- tension operable by means of a Spanner through which said wormscrew may receive slight angular movements with respect to the rictionally coupled pin for restoring the pointer to the zero position on the dial.

FRANCESCO MALAGRINO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 443,869 Riglander Dec. 30, 1890 694,028 Protherode Feb. 25, 1902 1,145,922 Rigamont July 13, 1915 1,194,182 Kaplan Aug. 8, 1916 1,245,324 Droitcour Nov. 6, 1917 1,274,331 Rockwell July 20, 1918 1,355,724 Zhukoi` Oct. 12, 1920 1,488,984 Heyne Apr. 1, 1924 1,528,314 Wickman Mar. 3, 1925 1,621,526 Culell Mar. 22, 1927 2,173,519 Jones Sept. 19, 1939 2,210,435 Ruf Aug. 6, 1940 2,282,114 Brister May 5, 1942 FOREIGN PATENTS Number Country Date 26,007 Sweden Dec. 12, 1908 63,052 Germany June 27, 1892 408,394 Great Britain Apr. 12, 1934 

